Were the ancient Greek gods and goddesses worshipped as if they were real entities?

For the most part, the Greeks did worship their Gods as if they were real entities, just as the Christians worship their God. The temples they built and the sacrifices they made were very important to their culture. Some Gods, such as Bacchus could possibly be considered a God that was "created" to enrich local arts. The same thing went for the Romans. It wasn't until the later Roman republic, when it was being inundated with religions for all over that they began to worship them as more of an "idea" rather than a real entity, which was right before the conversion of the empire to Christianity by Constantine.